1. Field of the Invention
The present invention relates to a display apparatus using the same, and a drive method therefor, and, particularly, to a display drive apparatus adaptable to a display panel (display pixel array) having an array of a plurality of current driven type (or current controlled type) emission devices each of which emits light at a predetermined luminance gradation as a current according to display data is supplied thereto, a display apparatus using the same, and a drive method for the display apparatus.
2. Description of the Related Art
Recently, there are active studies and developments on emission device type display apparatuses (emission device type displays) each having a display panel with a matrix array of current driven type emission devices, such as organic electroluminescence devices (organic EL devices), inorganic electroluminescence devices (inorganic EL devices) or light emitting diodes (LEDs), as the next generation display devices to the liquid crystal display apparatus.
Particularly, an emission device type display adopting an active matrix drive system has very superior features of having a faster display response speed and less dependency on the angle of visibility, and requiring no backlight nor light guide plate, as compared with the known liquid crystal display apparatuses. Therefore, there is an expectation of application of such an emission device type display to various electronic devices.
As such an emission device type displays employing the matrix drive system, there is known an organic EL display apparatus using organic EL devices as emission devices, which employs a drive system to control the luminance gradation by controlling the current flowing to the emission devices based on a voltage signal.
In this case, at each display pixel, there are provided a current control thin film transistor which has a gate applied with a voltage signal according to display data and lets a current having a current value according to the voltage value of the voltage signal flow to an emission device, and a switching thin film transistor which performs switching to supply a voltage signal according to the display data to the gate of the current controlling thin film transistor.
In such an organic EL display apparatus which controls the luminance gradation by setting the current value of the current flowing to the emission devices based on the voltage value of the voltage signal applied according to display data, however, the threshold value in the electric characteristic of the current controlling thin film transistor or the like may change with time. When such a change in threshold value occurs, the current value of the current flowing to the emission device varies even with the same voltage value of the voltage signal to be applied according to display data, so that the emission luminance of the emission device changes, which may impair the display characteristic.